Laminated panel and method of making the same



Aug. 1, 1950 V I L- B- WEYMOUTH LAIIINATED PANEL AND METHOD OF MAKING THE SAIE Filed Jan. 8, 1947 IN V EN TOR. Jaw/20a: ,3. Manual;-

Arr-r0! EM Patented Aug. 1, 1950 LAMINATED PANEL AND METHOD OF THE SAME Lawrence B. Wennouth, Grosse Pointe Farms, Mich., assignor to Brit" Manufacturing Company, Detroit, Mich, a corporation of Michigan Application January 8, 1947, Serial No. 720,909

5 Claims. 1 The present invention relates to a panel-like structure or article and to its manufacture, relating more particularly to a panel especially useful for trimming the interior-of vehicle bodies such as automobile bodies.

in the manufacture of panels or similar articles having the strength, rigidity, and decorative appearance required for the purpose mentioned, it has been customary to provide a dense, comparatively heavy foundation sheet or layer. For example, this foundation sheet may be formed of sheet metal, a compacted fibrous substance such 1d a plastic impregnated fibrous material, a laminated material such as plywood, and the like. Since materials of this character are hard and provide no cushioning effect, it has also been customary to cover the base sheet with wedding or padding which lies underneath an outer fish covering of cloth or other fabric material. One lrnown method of securing the fabric finish covering to the interior of the panel involves the use of an adhesive or bonding materlal such as a resin. some dimculties have been encountered in securing the fabric material by such means. wedding or padding usually absorbs crrcesslve quantities of the material, thus wasting it; also, there is a tendency to spread the adhesive unevenly since it soalrs into the padding in an unpredictable manner. As a consequence, the fabric may be tightly secured in spots and unsecured in others, which causes wrinkles and which tends to stretch the cloth in an undesirable manner. liarious attempts to overcome these dimculties have proved but partially successful, such, for instance, as coating the padding with adhesive material or spraying adhesive material over it.

it is, therefore, one object of the present invention to provide an improved panel or similar article as well as a method for fabricating the same, in which wedding or padding is eliminated without impairing the rigidity, strength, or decorative appearance of the panel, while at the some time providing a panel having the desired cushioned or yieldable outer surface.

it is another ohiect of an; invention to secure a fabric covering to the interior parts of a panel in a smooth and even manner while employing the minimum quantity of bonding material consistent with holding the fabric in place effectively, thus avoiding loss or waste of such material as well as minimising the danger of having the bonding material soalr through the fabric and spoil the appearance of the panel and avoiding the danger of having the fabric secured too tightly to the panel in some places and too loosely in others.

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It is another and somewhat more specific: object of the invention to include, as a part of the panel, an interior sheet or layer formed of a material which is stiff enough to provide a supporting foundation but which is, nevertheless, somewhat compressible so that it functions in place of wedding or padding to provide a cushioning effect beneath the outer fabric covering.

Finally, it is an object of my invention to provide a panel of the foregoing character and to provide a method of fabricating it which does not require expensive or scarce materials, which is adapted for mass production methods, and which produces a substantially waterproof but inexpensive article as well as one which is suciently rigid, strong, and pleasing in appearance to be employed as satisfactorily for trimming the interior of vehicle bodies as generally similar panels made from more expensive materials and manufactured in accordance with much more elaborate methods.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein lilre reference characters designate correspond ing parts in the several views.

Fig. l is a side elevation of a trim panel constructed in accordance with the present invention.

Fig. 2 is an exploded, perspective view of the parts of the trim panel shown in Fig. 1 prior to their consolidation to form the panel.

Fig. 3 is a cross-sectional view of a portion of the trim panel shown in Fig. l and is taken along the line t-d of Fig. 1 looking in the direction of the arrows.

Before explaining in detail the present invention, it is to be understood that the invention is not limited in its application to the detail of construction and arrangement of parts illustrated in the accompanving drawings, since the invention is capable of other embodiments and of being practiced or carried out in various wavs. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

in the drawings. there is illustrated by way of example one embodiment of the invention, namelv, an ornamental trim panel indicated generally at it. This trim panel is adapted to be mounted on the inside of an automobile door immediately below the window opening. it is intended to cover the inner metal door panel and provides an ornamental or decorative finish for the inside of the door. Generally speaking, the trim panel it comprises an outer fabric covering it provide its outer surfaces.

which is secured to an inner supporting sheet or layer indicated generally at I2 (Fig. 2). This inner sheet or layer I2 includes a form-sustaining and supporting core shown at It, having facing sheets I! and I9 secured at either side to The form-sustaining foundation I2 is formed from a relatively light material, that is, a material having a low density, and it is at least somewhat compressible. The resin-impregnated sheet ll serves as a bonding means for securing the fabric I I to the foundation sheet I2, while the resin-impregnated sheet III serves to waterproof the foundation sheet I2 and to stiffen it. As best shown in Fig. 2, the fabric material II is superimposed upon the sheet ll, the sheet I4 is superimposed upon the foundation I2, the sheet I5 is placed beneath the foundation I2, and all of these elements are compressed together and consolidated in a press under the influence of heat and pressure to form the unified panel structure in the manner more fully pointed out hereinafter. In so consolidating the elements of the panel, I have preferred to form ornamental grooves or depressions which may follow any desired design or pattern in the localities of which the various laminations of the panel are especially firmly bonded together. In Fig. 1, these ornamental grooves or depressions are indicated generally at I6 and I1 and provide the generally rectangular designs shown. It will be understood that the design or pattern applied to the panel and the configuration thereof in Fig. 1 are shown solely for the purpose of illustration, since such designs or patterns may vary widely in accordance with the taste of the designer. Also, it will be understood that the trim panel I0 particularly illustrated is given by way of example only, since trim panels for other purposes could be made in accordance with the present invention and such panels have a wide variety ofuses.

Referring to the construction of the trim pane in greater detail, the form-sustaining portion or member I2 serves as a foundation sheet or layer for the entire structure. This sheet or layer should be formed of a material which is comparatively light and which is compressible but which is rigid and strong enough to support the panel properly. It may possess a spongy structure, it may be of a cellular construction, or it may possess some equivalent physical characteristics rendering it capable of supporting the fabric as well as the other layers of the panel, while having a low density. I have preferred to use a cardboard material generally known as corrugated board-which comprises an interior core, shown at I3, of a wavy construction faced on both sides with sheets of cardboard I8 and I9 in the manner best shown in Fig. 2. However, other materials may be employed, such as balsa wood, paperboard, another type of cardboard material called honeyboard, or a cellulosic, spongy product often referred to as cellular board.

'I have preferred not to impregnate the formsustaining foundation I2 with a plastic, or a resin, or with other substances commonly used to stiffen or waterproof materials of the nature discussed. However, it is possible to use an impregnated material toform the foundation I2 provided that the material does not stiffen and harden it excessively and, in particular, does not harden it to such an extent as to'render it dense and incompressible. For example, I have employed socalled asphalt board, that is, a corrugated paper board similar to that discussed above but which 4 has been impregnated with 15% to 25% by weight of asphalt or a similar bituminous material. As pointed out, however, I have preferred not to impregnate the board and have found it desirable to keep the content of the impregnating material low, if any is used.

The sheets I4 and It may be of any material adapted to absorb a resinous or plastic material provided that they are thin and capable of withstanding handling. I have preferred to use cellulosic material such as thin alpha cellulose paper sheets or some equivalent white wood pulp paper having a fine grain. It is preferable to impregnate these sheets I4 and IS with a thermo-setting resinous substance such as a phenol-formaldehyde resin. It is also the preferred practice to convert the resinous substance into a varnish by dissolving it in a suitable solvent and to impregnate the sheets I4 and I5 by immersing them in the varnish so that their fibers may become thoroughly saturated. The sheets II and I5, after being impregnated in the manner indicated, are dried. After the comparatively volatile solvent has been expelled during the drying operation, theresinous material is partially reacted or poly-' merized. However, the resinous material is capable of further reaction. In other words, it has been placed in the so-called B stage. I

In order to assemble and consolidate the various parts of the panel, the elements are arranged.

in the general way indicated in Fig. 2, that is, the sheets I 4 and I5 containing their partially polymerized resinous material are placed on each face of the inner supporting element l2, and the fabric covering material is superimposed upon one of the resin-containing sheets, such as sheet I4. In practice, these elements I3, I4, and I5 actually rest upon each other, although they are shown separated in Fig. 2 for the purpose of clearer illustration. The fabric material Il may be any suitable covering or upholstering material such as cloth, artificial leather, heavy paper, or the like, depending upon the purpose for which the panel is intended. I have selected a suitable relatively coarse cloth commonly used for upholstering the interior of automobile bodies.

After the foundation board 12, the sheets I4 and I5, as well as the fabric I I have been assembled in the way indicated in Fig. 2 and described above, they comprise a laminated article in which the inner elements constitute plies faced by the fabric II onone outer surface and the paper sheet I5 0n the other outer surface. These laminations or plies rest on each other, although at this stage they are not consolidated together.- The laminations grouped in this manner are placed on a suitable conveyor or are otherwise transported to a press. The press is provided with heated upper and lower platens. The panel is pressed while being heated by the platens and is consolidated or unified to form the completed article. During the pressing operation, the temperature and pressure are so'regulated that the resinous material contained in the sheets I4 and I5 is cured, but first it contacts or infuses into the foundation board as well as the fabric sheet II and forms a bonding or adhesive means for securing all of the elements of the panel together.

Preferably, the press is provided with dies which may be carried by the heated platens re-- ferred to, or a single die element may serve as a combined platen and die. These dies are designed to provide the grooves shown generally at l6 and I1. More particularly, I have provided a female die grooved to provide the desired design and a corresponding punch or male die adapted to press the laminations of the panel together to compress them in the area of the rooves and to provide the resulting indentations or depressions forming the desired design. A cross section of two such indentations is shown at 20 and 2| (Fig. 3). Not only does my procedure provide a more ornamental panel, but it causes all of the layers of the panel to adhere securely together, not only because such layers are compressed at the grooves, but because the resinous material in the area of the grooves flows through the fabric material and is cured to provide an additional means for firmly adhering the fabric material to the inner parts of the panel. 7

After the pressing operation mentioned, the panel may be considered as completed, although it may be desirable to trim it or to fold edges of the fabric material over the back of the panel and secure them in place. I have preferred to provide a. fabric material which terminates at the edge of the panel and have found the trimming operation unnecessary for a panel intended to be used as an interior trim panel in a vehicle body.

It should be noted that resinous material in the sheets I4 and I5, particularly in the sheet I 4, is evenly distributed over the surface of the sheet [4' and consequently over the surface of the fabric material I I. Furthermore, it is a comparatively simple matter to determine the optimum quantity of material necessary to adhere the various elements of the panel together without using an excessive quantity. As a result, the fabric material is firmly and uniformly secured to the inner parts of the panel without having the resinous material soak through the fabric material to deface the panel except, of course, in the area of the grooves where it is intended that the resinous material penetrate the fabric. It will also be observed that the foundation board is somewhat compressible and at the same time possesses a low density. The corrugated board illustrated is particularly useful for these purposes since the paper from which it is formed is at least somewhat compressible and the corrugated structure of the core I3 renders the foundation board still more compressible. However. other paper board, such as honeycomb board and various cellulosic products, also serve well as a foundation sheet. A panel constructed in accordance with my invention contains no wadding or padding of the usual character such as felt. cotton batting. or the like. But the panel is rigid, strong, and possesses a pleasing decorative appearance while at the same time having a somewhat yieldable or cushioned surface which is desirable and which the padding normally provides. Thus, a satisfactory panel may be made inexpensively while avoiding the disadvantages of wadding or padding without detracting from the desirable characteristics of the panel.

I claim:

1. A trim panel comprising a base composed of a relatively thick sheet of stiff but compressible corrugated board having a thin paper sheet of uniform texture permanently secured to the bottom surface thereof through the medium of a resinous material, a top sheet, and a thin resin gether, said board and sheets being compressed together in certain regions and substantially uncompressed in adjoining regions to leave the board in the latter regions substantially undeformed.

2. A trim panel comprising a base composed of a relatively thick sheet of stiff but compressible board of low density and cellular structure having a thin sheet bonded to the bottom surface by a resinous material, a top sheet, and a thin resin impregnated paper sheet of uniform texture interposed between said top sheet and board and providing the sole means for bonding the same together, said board and sheets being compressed together in certain regions and substantially uncompressed in adjoining regions to leave the board in the latter regions substantially undeformed.

3. A method of fabricating a panel, including the steps of laminating a plurality of sheet including a form-sustaining base sheet of corrugated board having a resin impregnated sheet secured to the bottom surface thereof a top fabric sheet and an absorbent fine grain paper sheet of uniform texture impregnated with a reactive thermo-setting resinous material interposed between said base and fabric sheets, and subjecting said sheets to a hot pressing operation to consolidate the sheets together with the corrugated board and fabric sheet permanently bonded together solely through the medium of said paper sheet and with the corrugated board remaining undeformed throughout the major area thereof. 4. A laminated panel comprising a bottom thin paper sheet of uniform texture impregnated with a resinous binder, a relatively thick sheet of compressible corrugated board superimposed upon said paper sheet, a thin paper sheet of uniform texture impregnated with a resinous binder and superimposed upon said board, and a top decorative sheet superimposed upon said second named paper sheet, said corrugated board and said top sheet being bonded together through the medium of said second named sheet and said bottom paper sheet being bonded directly to the bottom surface of said board to reinforce and waterproof the same.

5. A laminated panel comprising a bottom thin paper sheet of uniform texture impregnated with a resinous binder, a relatively thick sheet of compressible corrugated board superimposed upon said paper sheet, a thin paper sheet of uniform texture impregnated with a resinous binder and superimposed upon said board, and a top decorative sheet superimposed upon said second named paper sheet, said board and sheets being consolidated together under heat and pressure to permanently compress portions thereof together at the locality of relatively narrow grooves while leaving portions of said corrugated board adjoining said grooves substantially undeformed by any compressive action during the consolidation of the sheets and board.

LAWRENCE B. WEYMOU'I'H.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,960,176 Weber et a1 May 22, 1934 2,187,335 Wagner Jan. 18, 1940 2,287,159 Zinser June 23, 1942 2,303,195 Buff Nov. 24, 1942 2,454,719 Scogland Nov. 23, 1948 

2. A TRIM PANEL COMPRISING A BAS COMPOSED OF A RELATIVELY THICK SHEET OF STIFF BUT COMPRESSIBLE BOARD OF LOW DENSITY AND CELLULAR STRUCTURE HAVING A THIN SHEET BONDED TO THE BOTTOM SURFACE BY A RESINOUS MATERIAL, A TOP SHEET, AND A THIN RESIN IMPREGANTED PAPER SHEET OF UNIFORM TEXTURE INTERPOSED BETWEEN SAID TOP SHEET AND BOARD AND PROVIDING THE SOLE MEANS FOR BONDING THE SAME TOGETHER, SAID BOARD AND SHEETS BEING COMPRESSED TOGETHER IN CERTAIN REGIONS AND SUBSTANTIALLY UNCOMPRESSED IN ADJOINING REGIONS TO LEAVE THE BOARD IN THE LATTER REGIONS SUBSTANTIALLY UNDEFORMED.
 3. A METHOD OF FABRICATING A PANEL, INCLUDING THE STEPS OF LAMINATING A PLURALITY OF SHEETS INCLUDING A FORM-SUSTAINING BASE SHEET OF CORRUGATED BOARD HAVING A RESIN IMPREGNATED SHEET SECURED TO THE BOTTOM SURFACE THEREOF, A TOP FABRIC SHEET AND AN ABSORBENT FINE GRAIN PAPER SHEET OF UNIFORM TEXTURE IMPREGNATED WITH A REACTIVE THERMO-SETTLING RESINOUS MATERIAL INTERPOSED BETWEEN SAID BASE AND FABRIC SHEETS, AND SUBJECTING SAID SHEETS TO A HOT PRESSING OPERATION TO CONSOLIDATE THE SHEETS TOGETHER WITH THE CORRUGATED BOARD AND FABRIC SHEET PERMANENTLY BONDED TOGETHER SOLELY THROUGH THE MEDIUM OF SAID PAPER SHEET AND WITH THE CORRUGATED BOARD REMAINING UNDEFORMED THROUGHOUT THE MAJOR AREA THEREOF. 